MUAC Percentile Calculator
Calculate mid-upper arm circumference (MUAC) z-scores and percentiles using WHO expanded reference (approximately 3 months to 6 years). Useful when weight measurement is impractical or as a supplementary nutrition screening tool.
How to interpret MUAC percentiles
Mid-upper arm circumference (MUAC) is measured at the midpoint between the acromion and olecranon with the arm relaxed. WHO expanded arm circumference references provide z-scores and percentiles by age and sex for roughly 3 months to 6 years.
MUAC complements weight and length assessment, especially in resource-limited settings or when a standing scale is unavailable. Very low MUAC percentiles may indicate acute malnutrition and warrant full nutritional and clinical evaluation per local protocols.
Sources and Reference Basis
WHO expanded arm circumference reference LMS data. MUAC is a supplementary anthropometric measure; interpret with weight-for-length/height and clinical context.
- WHO Child Growth Standards — arm circumference Reference basis for MUAC z-scores.
- WHO infant growth calculator Weight and length percentiles for infants.
- Growth calculators hub All pediatric growth tools.
Related
Frequently Asked Questions
What age range does this MUAC calculator cover?
Approximately 3 months to 6 years (72 months), using WHO expanded arm circumference reference data.
How is MUAC measured?
Measure at the midpoint of the upper arm (between shoulder and elbow) with a non-stretch tape, arm relaxed at the side.
Can MUAC replace weight-for-length?
No. MUAC is a supplementary screening tool. Full nutritional assessment should include weight, length/height, and clinical evaluation.